Almost 30 kilograms of plastic are responsible for the death of the sperm whale that washed ashore on 27 February on the Spanish coast in the region of Murcia. This is what the autopsy results conducted by the Wildlife Recovery Centre of El Valle (Centro de recuperación de fauna silvestre El Valle) reveal. It is not the first case and unfortunately will not be the last, but 30 kilograms is a striking amount.

The autopsy results

The autopsy revealed that the specimen was a young male, nearly ten metres long and weighing 6.5 tonnes. The internal examination found in its digestive tract (stomach and intestine) 29 kilograms of marine waste such as rubbish bags, raffia sacks, ropes, pieces of netting and even a drum.

The experts at the Centre that carried out the analysis believe that the plastic material found in the stomach may be the cause of the animal's death because it most likely generated peritonitis or in any case an infection in the digestive system. The animal was in fact unable to expel the plastic.

The sperm whale: an endangered species

The sperm whale (Physeter macrocephalus), a cetacean of the Odontoceti family, is the largest species among all toothed cetaceans and its natural diet consists of squid and fish, totalling around 910 kilograms per day.

Among the twelve species of cetaceans found in the Mediterranean, the sperm whale, together with the common dolphin, are endangered species according to the Red List of the Iucn (International Union for Conservation of Nature).

The drama of plastic at sea

There are no cetacean sanctuaries, such as the one in the Ligurian Sea, that can protect marine animals from plastic, which is now present everywhere. Eighty per cent of waste found at sea is of anthropogenic origin and comes from land, while the remaining 20 per cent comes from ships.

Plastic islands are not only found in the Atlantic or Pacific oceans, but also in the Mediterranean. "The presence of plastic in seas and oceans is one of the greatest threats to wildlife conservation worldwide, given that many animals become trapped in rubbish or ingest large quantities of plastic that end up causing their death," commented Consuelo Rosauro, director general of the natural environment in the Government of Murcia.

The region of Murcia, whose beaches are particularly affected by plastic pollution, has launched a campaign to raise awareness among citizens that includes initiatives to clean the beaches, using the "Ocean Conservancy" action protocol, which makes it possible to obtain data on the type and quantity of marine waste. Nineteen conferences and audiovisual presentations at educational and social centres in the Region are also planned, because starting with young people is essential.

Why marine animals eat plastic

Turtles and cetaceans eat plastic bags thinking they are jellyfish; sharks mistake pieces of plastic for fish. Birds too feed on plastic. Beyond the similarity in shape or appearance, it would seem, according to a study, that animals ingest plastic because it smells like food. Krill feed on algae. When these die and decompose, they emit a sulphurous smell generated by dimethyl sulphide (DMS). Animals have learnt that this smell indicates the presence of krill.